1. Field
The present invention generally relates to wireless communication systems, and more specifically to forward-link signal transmissions from a gateway to a wireless communication device having a single-polarization antenna.
2. Background
The rapid development of wireless communication systems has enabled people to stay connected while they move about or travel. Typically, land-based base stations are deployed to wirelessly couple a wireless communication device (e.g., wireless telephone) to other communication devices (e.g., other wireless telephones). However, it is often not economical or feasible to deploy base stations in rural or sparsely populated areas. In such situations, satellite-based wireless communication devices (e.g., satellite telephones) are able to provide a communication link without the need for land-based base stations. One or more geosynchronous or geostationary satellites orbiting the earth may be deployed to communicate with one or more wireless communication devices (e.g., satellite telephones).
Gateways and relaying satellites often employ polarized antennas, such as right hand circular (RHC) and left hand circular (LHC) polarized or vertical and horizontal polarized, to communicate with wireless communication devices.
The polarization of a wireless communication device is often random or unpredictable depending on how it is held by the user. That is, the polarization orientation of the communication device antenna varies depending on the device orientation and proximity to the user's head and hands, etc. Therefore, depending on the operating conditions, the LHC or RHC response of the nominally linear antenna may be stronger than the other. This may lead to degradation of the received signal and communication quality. Thus, matching the transmitted polarization to the orientation of the receiving antenna can improve the forward link transmission.